The present invention relates to an apparatus for the separation of a mixture of components, and more particularly to an improved centrifugal separator for separating molten metals, metal components or metal containing slags by centrifugal forces.
Centrifuges for separating phases of metal or metal compounds or metal and slags have been heretofore used wherein the centrifuge body was suspended by universal joint and driven in rotation. An example of such a metal centrifuge is disclosed in the German Laid-Open Specification No. 25 18 796, and in this structure, the charging material is introduced from above through a stationary charging hopper projecting into the interior of a rotating hollow shaft forming the centrifuging body. The liquid or molten metal such as a molten slag is deflected through a corotating deflecting apparatus to all areas of the centrifugal container and simultaneously accelerated in the direction of rotation. Discharge openings are located in the lower end of the centrifuge body for separated materials, and the body is bell shaped. In a metal centrifuge of this known type, difficulties are encountered in the presence of the necessity of absolutely uniform charging of the material into the separator. The liquid metal slag mixture must be poured, for example, out of a pouring ladle from above. In addition to the difficulty of uniform pouring from a ladle, the material encounters too high inertia in being deposited from above engaging the deflection apparatus in the interior of the centrifuge body with too high inertia.
Further, in this type of device, it is necessary to line the centrifuge, particularly in the discharge area, with a gas-tight material, or at least to provide a drive or barrier of inert or reducing gas to prevent a reoxidation of the centrifuged out hot metal particles. It is accordingly an object of the present invention to provide a mechanism for a metallurgical plant which is capable of centrifugally separating metals without the aid of special charging apparatus or complicating charging methods and to make possible the provision of a centrifuge which may be partially immersed in a bath of liquid metal or metal slag mixtures such as, for example, in an available casting or pouring ladle and to thereby adapt the centrifuge to the particular operating conditions present in existing metallurgical plants without the provision of special additional equipment.
The foregoing object is accomplished by a feature of the invention wherein the centrifugal body is provided at its lower area with a concentric aperture that is immersed below the liquid level of the material to be separated, and has provided in its upper area openings for centrifuging off of the separated components. The spacing of the openings for centrifuging off the separated components is greater than the radius of the concentric submerged opening. With this arrangement, the apparatus accomplishes a continual upward flow of layers of material being separated. In a preferred embodiment of the apparatus, the centrifugal body has a central hollow shaft with the lower area of the centrifugal body constructed as an immersion pipe. In a further preferred arrangement, the hollow shaft at least in the area of the immersion pipe is enclosed by a cooling sleeve constructed for conducting a cooling fluid. The apparatus further has a supporting basket surrounding the hollow shaft and being of larger diameter and carrying the centrifugal body. The supporting basket is also preferably enclosed by the cooling sleeve. The cooling sleeve is so constructed so that it is connected to inlet and outlet conduits for conducting a cooling medium. The immersion pipe is connected with the interior of the centrifugal body by means of radially extending conduits. The cooling medium flows to surround the immersion pipe of the sleeve and absorb heat in the immersed area and transfer the heat back, at least in part, to the wall areas of the centrifugal body contacted by the centrifuged material. This prevents deposits on the wall of the unit.
In one alternate arrangement of the structure, the centrifugal body is constructed in a frusto-conical shape with the body widening in an upward direction. The opening at the base of the centrifugal body has a collar recessed axially inwardly and additionally may have a flow conducting body therein. Both the collar as well as the flow conducting body effect a suction on the material in which the lower end is submerged to increase the flow into the chamber in which the material is centrifuged.
In consideration of the high stresses on the entry location of the centrifuge, the centrifugal body may be provided in the immersed area with a mouth piece made of a heat resistant, corrosion resistant and abrasion resistant material, such as, ceramic. Such a mouth piece may be constructed of a graphite casting or a blank or a molded body made of sintered resistant metal oxide or other material having similar physical properties.
In one embodiment the centrifugal body is provided with a plurality of layers wherein the inner layer is formed of a heat and corrosion resistant material and the inner layer is enclosed by an outwardly located insulating and supporting layer which is supported against an outer sleeve to receive and sustain radial forces.
Other objects, advantages and features, as well as alternate embodiments and structures which are intended to be covered herein, will become more apparent with a teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the specification, claims and drawings, in which: